Of course no such thing as NT replaces the OT.
First of all we have to determined Who is GOD? Do we have GOD of OT or we have GOD of NT? Is this is One GOD or two? Shame on those who thinks that OT obsolete, and the GOD of OT no longer relevant, which does not make any sense and reveal complete lack of knowledge and understanding of the Bible.
Is Jesus Christ Son of GOD and GOD Himself? If so, then we have only One GOD, because both of Them have identical Holy Spirit.
John 10.30
30."I and the Father are One."
This means that They think as ONE and do everything as ONE, They cannot think separately or contradict One Another in anything. They have same thoughts.
Only with slight difference that Jesus was created by His Father, but no one created the Father, He has no beginning.
John 14.28
28."You heard that I said to you, 'I go away and I will come to you.' If you love Me you would have rejoiced, because I go to the Father, the Father is greater than I."
Is Jesus the very first Creation of GOD Father? Yes, He is the First.
Colossians 1.15
5.He (Jesus) is the Image of the invisible GOD, the Firstborn of all creation.
It means He was "born" made before angels, before universe, before Earth, before everything that was created by GOD Father, Jesus is very first creation of GOD.
So, Who between Them created the rest of the spiritual and physical world? Father or Jesus His Son?
Hebrews 1.2
2.in these last days has spoken to us in His Son, Whom He appointed Heir of all things, through Whom (through Jesus Christ) also He (Father) made the world.
And if GOD Father created through Jesus, or by Jesus, does not matter, the world, this means that Jesus Christ is Creator of the universe and Earth, about which is written in the first pages of Genesis.
And if Jesus Christ created whole physical world, it means that He was the One Who manage our physical world from the Day One, He is the One Who chose Abraham, Isaac, and Jacob, He was wrestle with Jacob and renamed him to Israel, and then gave Jews the Torah, the Law, through His servant Moses. Jesus is full and complete representation of GOD Father on Earth, and there is no other god beside Him. As it written, He and His Father Are ONE.
So, there is your GOD of the Old Testament? Did Jesus ever contradict or disobeyed His Father?
Matthew 5.17-19
17."Do not think that I have come to abolish the Law or the prophets. I have come not abolish but fulfill.
18.Truly I say to you, until heaven and Earth pass away, not the smallest letter or stroke shall pass away from the Law until all is accomplished.
Does Jesus come up with His Own law? Never! He brought to as the Law of the Old testament. Jesus took from the OT only spiritual commandment and left the physical commandments behind, because physical commandments such as laws about rituals, sacrifices, about food, and so on, are no longer needed for a new chapter in human history of His presence on Earth.
Jesus took only spiritual commandments from the Law of Moses and kept them all intact, and on them He based all His teachings. Everything ever Jesus said, all related to the spiritual commandments of the Old Testament, and all spiritual commandments of the Law themselves are based on 10 Commandments, like our laws base on our constitution.
In OT, in order to achieve righteousness and holiness before GOD Jesus required from Jews to fulfill the whole Law, physical and spiritual commandments, because Old Testament was designated for Jews only, to make them holy before the Lord in order to serve Him. Foreigners also included in worship of GOD but only those who permanently lived among Jews in the land of Israel, they are treated as natives and had been under the Law of Moses as any other native Jew.
Holiness must reach a certain level in order for a human to be presented before GOD and to serve Him, anything less than that is not acceptable for GOD.
Now in Jesus time holiness and righteousness can be achieve only through spiritual commandments of the Law of Moses, which is much higher level of dedication and faith in GOD than in OT. Jesus took humanity from the "high school" of the OT into a "college" of NT, gradually raising the bar of spirituality higher and higher.
The Old Testament is the extension of the New Testament, and one cannot exist without another.
Many referring to the writing of Paul there Paul explained short comings of the Old Testament in spirituality, and Paul was completely right, but Paul also very well understood that the Old Testament based on the physical rituals just the beginning of much greater, higher, and more sophisticated Law of a New Covenant, solely based on the spiritual commandments of the Old Testament.
When Bible talks about Law of Christ, it does not mean a different law, but the same Law of the Old Testament but without physical statutes and commandments, and because of it the Law of spiritual commandments was renamed as a New Testaments (Covenant, Law).
The Old Law talks about sin and fear of punishment, but the Refurbished Law of Moses by Jesus talks about only spirituality. If person is spiritual, he or she does not need to be constantly reminded about good and evil, sin and righteousness as in OT, because a spiritual person knows all these by the heart from the spiritual commandments of the same OT taken out from OT by Jesus and given to people. Spiritual person already knows without Law how to do good and righteous deeds not out of fear of punishment like in OT, but of spiritual love of NT.
Peter rebuke those who twisted the words of Paul due to their inability to understand deep thoughts and meanings of Paul's writings.
2Peter 3.15-16
15.and regard the patience of our Lord as salvation. So also our beloved brother Paul wrote to you according to the wisdom given him,
16.speaking of this as he does in all his letters. There are some things in them hard to understand, which the ignorant and unstable twist to their own destruction as they do the other scriptures.
